Particle counter with liquid responsive start and stop means



July 1, 1969 T: BAN 'ET AL 3,453,438

PARTICLE COUNTER WITH LIQUlL) RESPONSIVLJ START AND STOP MEANS Filed May9, 1966 COUNTEQ CONTROL.

/ N VE N TORS United States Patent Claims Us. Cl. 250-218 5 ClaimsABSTRACT OF THE DISCLOSURE A particle counter for counting suspendedparticles, ,especially blood cells, in which a determined volume of theliquid to be measured is sucked through a check gate during 'a measuringperiod and a counting circuit comprising two electrodes is provided onboth sides of the gate. The liquid containing the particles to becounted starts and stops the counting process. A closed gas space isprovided above the check space. A pressure-alternating device, e.g. anincandescent filament connected over a switch to an electrical supplysource, 'or a piston, a diaphragm, a Sylphon membrane or the like, isconnected to said closed gas space for providing first a gas pressurefor drivingthe liquid out of the check space, and subsequently creatinga suction, sucking in the liquid and performing the counting of thesuspended particles.

The invention relates to a particle counter for counting suspendedparticles, especially blood cells.

There are already particle counters comprising a tube with check gate,dipped into a suspension tank, a counting space, two electrodes arrangedoutside and inside the check gate, inserted in the counting circuit andfitted with counting starter and arrester unit. The counters of thistype, which operate with a check gate by reason of conductivity, have tofulfill in general the following duties:

(at) The liquid to be measured is to be sucked through the check gateduring the measuring period;

(b) Counting of particles in determined volume must be provided, forwhich purpose, in general, the starting and arresting of the particlecounter unit will be necessary;

(0) Removal of the return liquid is to be provided for.

However manufacturing difiiculties are responsible for the fact thatthis kind of appliance has not yet appeared on the market.

It is the main object of the invention to provide a particle counter inwhich the above difiiculties and disadvantages will be eliminated, witha simple design and no manufacturing difiiculties.

The main aim of the invention is to eliminate from the instrument theelement causing the greatest problem and defect, i.e. the piston fordrawing in of the liquid to be checked, be it a mercury piston or apiston controlled mechanically from outside.

The disadvantages are entirely suppressed by the arrangement accordingto the invention, which provides a number of advantages. Due to theomission of the mercury, the accompanying inconveniences do not comeabout. The check liquid is exchanged check by check; the constant liquidchange will flush and cleanse the vessel and the check space in itsinterior, the check liquid does not sully the check space and no deposittakes place. No flow off, no evaporation of the check liquid ispossible; therefore no crystallization of the liquid can be observed. Inview of its advantageous embodiments no packing problems will arise;even in piston arrangementswhich are believed to be the leastadvantageous-the requirements for the piston are extremely moderate,because the material seepage, due to defective packing of the piston,does not alter measurement. For volume, it is the displacement of theliquid surface that will be indicated. The instrument can be realizedwithout any moving parts. Special advantage of the instrument accordingto the invention is the fact that manufacture is simple and easy. It isextremely well adapted to be portable.

In the particle counter according to the invention, com prising a tube,a check space dipped into a suspension tank and fitted with a checkgate, as well as two electrodes arranged outside and inside the checkgate, inserted in the counting circuit, and having counting start andstop elements, these advantages are achieved by the fact that itcomprises a gas space, communicating from above with the check space,limited by the actuating plane of the starting and arresting elementssaid gas space being separated from the surroundings, which gas space isfitted with a gas pressure regulator, a flap valve, opening on thesurroundings, being connected with the side-joining to the tube fittedwith the check gateof the check space opposite to the gas space.

Further details of the parictle counter according to the invention aredescribed in the drawing representing an embodiment by way of example.

FIG. 1 shows an arrangement fitted with an incandescent filamentcontaining pressure regulator and shows an arrangement of installedstarter and arrester electrodes, and

FIG. 2 represents details of a Sylphon diaphragm arrangement, fittedwith external photoelectric indication.

As can be seen on FIG. 1, a tube 4 fitted with a one- Way check gate 3,which preferably fits by means of customary ground glass filling 5 to acounter body 6, reaches down into a receptacle 2 containing asuspension 1. In the body 6, there is formed a check space 9, limited byhorizontal planes located by the ends of the electrodes 7 and 8, thevolume of which space 9 is known. A gas space 10, in which anincandescent filament 11 is installed, adjoins from above to the checkspace 9. This is preferably fixed in a cover 12 made of insulatingmaterial which supports also the electrodes 7 and 8. The cover 12 sealsairtight the gas space 10 and its clamping is provided by hold-downs notrepresented on the drawing. Upstream from and downstream from the checkgate 3 electrodes 13 and 14 are arranged in the known manner. At theextremity of a pipe 15 of the body 6 there is a flap valve 16, closed bya valve rubber similar to that applied for instance in bicycles. Underthe outlet of the flap valve 16 preferably a vessel 17 is placed forreceiving the removed liquid. The electrodes 13 and 14 are inserted inthe particle counting circuit, and the electrodes 7 and 8 in the controlcircuit of starting and arresting the counting circuit. The incandescentfilament 11 is connected through a not represented switch with a currentsource that will make the incandescent filament glow after the switch isclosed.

The operation of the device is easy to understand. For starting theapparatus will be filled up, preferably from belowby applying afunnelled pipe for instance, instead of the pipe 4, with a liquid,perhaps with part of the liquid to be checked, up to a certain level,for instance up to the line 18. The only requirement for the liquid isto possess sufiicient conductivity to operate the counting starter andarrester circuit. Also the pipe 4 is filled up, then placed back. Thereceptacle 2 containing the suspension 1 to be checked is put around thepipe 4, and then the incandescent filament 11, being switched on to thecurrent source, will be caused to glow to a proper extent. Under theinfluence of heat the air enclosed in the gas space will expand andpress the liquid below the level, the excess liquid will flow outthrough the pipe 1 and the flap valve 16. Measurement can then berepeated constantly, i.e. can be continued.

In the variant illustrated on FIG. 2 a Sylphon diaphragm 19 is installedin the gas space 10, with the installation represented schematically.The liquid level is lowered below the lower level-of the check space 9by pressing this diaphragm by means of a push button 20. Indicating ishere etfected by means of light-sensitive cells 23 and 24 cooperatingwith the light sources 21 and 22, the plane of which constituteslimitation for the upper and lower planes of the check space 9. In thiscase the electrode 14 plays no part in starting and arresting thecounting, it takes part only in particle counting. The working of theinstrument corresponds to what has been described in connection withFIG. 1, in every respect.

As can be seen, in the instrument according to the invention the pistoncould be eliminated entirely, as the depression following the loweringof the liquid level exerts intake action on the liquid to be checked; itis this intake action that will suck the liquid through the check gateand makes possible particle counting in the usual way.

We claim:

1. A particle counter comprising a tube having a check gate, asuspension tank in which said check gate is immersed, two electrodesdisposed one downstream from and one upstream from the check gate, acounter in electric circuit with said electrodes, means responsive tothe presence of liquid in the tube at a first level for starting saidcounter, means responsive to the presence of liquid in said tube at asecond level above said first level for stopping said counter, and meansfor increasing the pressure in the tubeto drive liquid in the tubebelow-said first level.

2. A particle counter as claimed in claim 1, said liquid levelresponsive means comprising two electrodes thlower ends of whichterminate at said levels. 1

3. A particle counter as claimed in claim 1,' said liquid levelresponsive means comprising light sources and photosensitive cellsdisposed at said first and second levels.

. 4. A particle counter as claimed in claim 1, and a pipe connected tosaid tube and extending laterally therefrom, and a valve closing the endof said pipe but opening under said increased pressure to discharge fromthe pipe liquid forced below said first level by saidpressure-increasing means. I

5. A particle counter as claimed in claim 1, communicating downwardlyfrom said liquid level responsive means to said check gate.

References Cited UNITED STATES PATENTS y,

Carrick 250-218X 2,555,674 6/1951 2,599,975 6/1952 Carpenter 250 218 X2,684,008 7/1954 Vonnegut 88---14 2,844,066 7/1958 Friel 88'I143,345,502 10/1967 Berg et a1 23592 WALTER STOL'WEIN, Primary Examiner. N

US. Cl. X.R.

